Are You Getting Enough Sleep to Lose Weight?

In the last 40 years, the average duration of nightly sleep has decreased by 1-2 hours (1), a time during which the number of people classified as overweight or obese has doubled. It's been hypothesised that there is a correlation between these two trends: and it's not just because more waking hours means more time to eat.

Research has found that sleep deprived rats eat more than rats that are allowed normal amounts of sleep (2,3) . And several studies with human subjects show that people who sleep less are more likely to be overweight (4).

The cause is believed to be two hormones that regulate appetite and energy expenditure: Ghrelin and Leptin. The level of Leptin, a hormone that suppresses appetite, is decreased with sleep deprivation; and the level of Ghrelin, a hormone that stimulates appetite, is increased with sleep deprivation. So if you are trying to lose weight it's important that you are getting enough sleep.

How Much Sleep is Enough?

There's no perfect level of sleep for everyone, but the following table identifies the 'rule-of-thumb' amounts most experts have agreed:

Age / Sleep Needs Per Night (hours)
1-2 months: 10.5 - 18
3-11 months: 9-12 + 1-4 x 0.5 - 2 hour naps
1-3 years: 12-14
3-5 years: 11-13 hours
5-12 years: 10-11 hours
11-17 years: 8.5-9.25 hours
Adults: 7-9 hours
Older adults: 7-9 hours

To determine your own sleep needs, assess how you feel with different amounts of sleep.

How Can I Get More Sleep?

1. Make sleep a priority - don't make it the thing you do when everything else is done. If you have a daily planner; schedule sleep into it.
2. Drink a glass of milk before going to bed. Milk contains the amino acid Tryptophan, which may facilitate sleep.
3. Don't eat in the 2-3 hours before going to bed and aim to go to bed feeling content (i.e. neither full nor hungry). Going to bed hungry can affect your sleep as much as going to bed on a full stomach.
4. Exercise on a regular basis; avoiding the three hours before your bedtime. Some people exercise close to bedtime in the hope it will exhaust them; but this tactic can backfire as exercise stimulates the body by increasing your heart rate and metabolism.
5. Reduce your alcohol consumption. Although alcohol may help you fall asleep, it can disrupt your normal sleep pattern during the second half of the night and leave you feeling tired.
6. Avoid caffeinated drinks and foods after midday. This includes coffee, tea, cola and chocolate. If you are having trouble sleeping; try avoiding caffeine entirely and see if your sleep patterns improve.
7. Avoid smoking in the six hours before your bedtime (nicotine is a stimulant).
8. Avoid drinking too many fluids before bedtime to minimise night time urination.

References:

1. National Sleep Foundation, 2002, 'Sleep in America'
2. Danguir J and Nicolaidis S. 1979, 'Dependence of Sleep on Nutrients' Availability' Journal of Physiology and Behaviour vol. 22, pp. 735-740.
3. Everson CA, Bergmann BM, Rechtschaffen A. 1989, 'Sleep Deprivation in the Rat: III. Total Sleep Deprivation' Sleep vol. 12 pp. 13-21.
4. Hasler G, Buysse D, Klaghofer R, Gamma A, Ajdacic V, et al. 2004, 'The Association Between Short Sleep Duration and Obesity in Young Adults: A 13-year Prospective Study' Sleep vol.27 pp. 661-666.